Polymorphisms within the novel type 2 diabetes risk locus MTNR1B determine beta-cell function - Staiger, H; Machicao, F; Schafer, S A; Kirchhoff, K; Kantartzis, K; Guthoff, M; Silbernagel, G; Stefan, N; Haring, H U; Fritsche, A (PLoS One, 2008)